There are various types of ring binders available with the most common employing three separable ring assemblies spaced at fixed locations on a metal backing member. Front and rear covers extend from a backing strip which is typically riveted to th backing member. The ring assemblies usually have complementary arcuate ring halves, having fixed ends anchored to the backing member. Typically, a spring assembly is included for biasing the opposing ring halves into engagement. The ring halves are separable into an open locked position when sheets are added to or removed from the binder. In some binders, the rings may be separated by pulling on the opposite ring halves while in others a pressure element, acting through the backing member and having handles disposed at one or both ends of the backing member may be provided to effect release.
In U.S. Pat. No. 3,833,308, a binder fixture is disclosed using a stationary base plate with T-shaped rails extending across an upper surface thereof, a channel formed in a lower surface thereof, and a pair of slots extending through the base plate of the channel. A longitudinally extending cam bar slides within the channel and has pins projecting through the slots in the bas plate. A slide plate is provided having T-shaped slots complementary to and in engagement with the T-shaped rails to permit a sliding movement of the slide plate on the base plate. Sliding the cam bar causes the ring halves on the base plate to separate.
Such ring separators require multipart construction and assembly, at increased cost and complexity. While such ring separators have been used, the search continues for improved separator mechanisms of simple construction which may be produced at lower cost yet which can function with fewer constraints.